#include <stdio.h>

int main(int argc, char const *argv[])
{
    printf("你好\n");

    int hour1, minute1;
    int hour2, minute2;

    scanf("%d %d", &hour1, &minute1);
    scanf("%d %d", &hour2, &minute2);

    int ih = hour1 - hour2;
    int im = minute1 - minute2;

    if ( im < 0 )
    {
        im = 60 - im;
        ih --;
    }

    printf("时差是%d小时%d分钟\n", ih, im);

    return 0;
}